On Wed 2009-03-25 18:42:41, Li Yang wrote: > On Tue, Mar 24, 2009 at 12:54 AM, Scott Wood <scottw...@freescale.com> wrote: > > On Sun, Mar 22, 2009 at 10:45:23PM -0700, Li Yang-R58472 wrote: > >> > I don't think so, in this case. The user is not asking for > >> > "sleep" or deep sleep"; they are asking for a power state > >> > that meets the definition of "standby" (which sleep does) or > >> > which meets the definition of "mem" > >> > (which both sleep and deep sleep do). When the user asks for > >> > "mem", we provide the lowest power mode that qualifies. > >> > >> In my understanding, "mem" which is suspend-to-ram means all CPU states > >> and registers are kept in memory and the CPU is completely off during > >> suspension. I don't think the sleep mode of 8349 qualifies, does it? > > > > Is there a difference visible to software or to the user (other than not > > achieving power savings that the board does not support)? It seems > > simpler for userspace to just specify the "heaviest" sleep state it wants > > deal with (though some feedback to an administrator of what actually > > happens would be nice). > > I agree that it's handy to have a "sleep" state in kernel to > automatically enter the "heaviest" sleep state supported. However it > is also very simple for user space script or application to check the > available states first and then enter explicitly the "heaviest" sleep > state. > > Pavel, what's the preferred way for current PM sub-system?
If you have single sleep state, use "mem" > /sys/power/state. If you have two, use mem and standby. Do you have more? > > > > And if we want to be really pedantic, neither sleep nor deep sleep meet > > the definitions for either "standby" or "mem", because they specify > > acceptable latency ranges in seconds, and (in the absence of a disk) we > > are much faster than that (it doesn't say "up to 1-2 seconds"). :-) > > > > Are there any existing suspend drivers that suppord standby but not mem? > > I see omap1 as a counterexample that treats them both the same. > > > > -Scott -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
